For example, consider, when a television (TV) program is being viewed, displaying on a screen information related to the TV program (hereinafter, simply referred to as program) (such as performers, an outline, or an announcement of the next episode), information useful for a viewer but not directly relevant to the program (such as news, a weather forecast, or traffic information), or the like.
This can be implemented by transmitting a command for a dedicated application program (hereinafter, abbreviated as application) to be acquired and started to a TV receiver or the like in synchronization with the progress of the program. This has actually been implemented in Japan, Europe, and others by transmitting the command and an application using a band for data broadcasting in a TV broadcast signal (for example, see Patent Document 1).
On the other hand, in the United States, a band for data broadcasting is not provided in a TV broadcast signal, and an alternative method has not been established. Thus it has not been implemented to execute an application in synchronization with the progress of a program.
In the United States, the number of households that view programs via CATV, IPTV, or the like is greater than the number of households that view programs by directly receiving TV broadcast waves by TV receivers. CATV and IPTV sometimes extract only video and audio signals of programs from TV broadcast signals for distribution. Therefore, even if a band for data broadcasting is provided in a TV broadcast signal in the United States, there will be no guarantee that data broadcast signals in which data on applications is included are transmitted to receiving apparatuses via a communication network of CATV or IPTV.
Further, these days, when any content such as a recorded program, a video reproduced from a package medium such as a DVD or a BD, or moving images downloaded from the Internet, as well as a program being broadcast in real time, is being viewed, there is a desire to execute an application in synchronization with the progress thereof.
In order to cause an application to be executed in accordance with the progress of any content being viewed, first, it is necessary to identify the content being viewed. As a method for that, the application of automatic content recognition technology (hereinafter, referred to as ACR) has been conceived.
In ACR, signature data is inserted into content such as a program to be viewed and provided to the viewer side, and at the same time, the content and the signature data are associated with each other to be databased. Then, the viewer side extracts the signature data from the content being viewed, checks it against the database, and thereby identifies the content being viewed.
For the kind of signature data that is inserted into content, provided to the viewer side, and extracted at the time of viewing, for example, a digital fingerprint (hereinafter, referred to as FP), a digital watermark (hereinafter, referred to as WM), or the like is used.
Operators that provide ACR services are not limited to broadcast stations. Various entrants are considered, and as a result, emergence of a plurality of ACR services is expected. The emergence of the plurality of ACR services causes an increase in the number of content registered in the database, so that an improvement in content identification accuracy can be expected. However, the kinds of signature data adopted in the plurality of ACR services are not necessarily unified.
On the other hand, on the viewer side, content identification accuracy can be increased by extracting a plurality of signature data pieces from content being viewed by extraction methods depending on the kinds of signature data adopted in the plurality of ACR services, and using the plurality of ACR services.